PREPARATION  OF  M-M  -DIHYDROXY 
DIPHENYL  ETHER 


HY 

CARL  WILLIAM  KUEHNE 


r 


rHESIS 


FOR  TH  K 


D E G R E E O E B A C II  ELOR  OF  SCIENG  E 

IN 

CHEMISTRY 


COLLEGE  OF  LIBERAL  ARTS  AND  SCIENCES 

UNIVERSITY  OF  ILLINOIS 


1922 


VU5  

UNIVERSITY  OF  ILLINOIS 

___Maxx__25 i92.2__ 

THIS  IS  TO  CERTIFY  THAT  THE  THESIS  PREPARED  UNDER  MY  SUPERVISION  BY 

C_ar_l  William  _Kuehne_ 

ENTITLED i on. _9 H ?_y  T&A Pi} ejiyi.  _ ©t he  r_  _ 


IS  APPROVED  BY  ME  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR  THE 
DEGREE  OF  c i_®.P_Q.§_ AH _Chemi f?  t.rZ 



Instructor  in  Charge 

Approved  \£j_._  

HEAD  OF  DEPARTMENT  OF 


<L.y  '<>  Ajt  J 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/preparationofmmdOOkueh 


ACKNOWLEDGMENT . 

The  author  wishes  to  express  his  deepest 

t 

appreciation  to  Dr.  Carl  S.  Marvel  for  the  helpful 
suggestions  and  optomistic  encouragement  which  were 
given  during  the  course  of  this  research. 


TABLE  OF  CONTENTS 


Introduction 

4. 

Theoretical  and  Historical 

5. 

Experimental 

8. 

Preparation 

of 

m-m-dimethoxy-diphenyl  ether 

8. 

Preparation 

of 

p -n  i t r o -b  r omo  -b  en  z en  e 

9. 

it 

n 

pot as sium-p -nitre  -phenol  at  e 

9. 

it 

tf 

p-p’-dinitro -diphenyl  ether 

10. 

tt 

tt 

p-p'-di  amino -diphenyl  ether 

11. 

Acetylation 

of 

p-p’-di amino -diphenyl  ether 

11. 

Nitration  of  p- 

-p’-diacet  amino -diphenyl  ether 

12. 

Preparation 

of 

m-nitro-benzene-diazonium  sulfate 

15. 

tt 

tt 

m-nitro -phenol 

15. 

tt 

tf 

pot assium-m-nitro -phenol ate 

16 . 

tt 

tl 

m -n  i t ro  -b  r omo  -b  en  z en  e 

17. 

tt 

tt 

m-m’-dinitro-diphenyl  ether 

17. 

Summary 

19. 

Bibliography 

20. 

4. 


INTRODUCTION. 

Resorcinol  ether,  or  m-m-dihydroxy- diphenyl  ether,  is 
recorded  in  the  literature  as  "being  prepared  by  treating  resorcinol 
with  HC1,  or  by  simply  heating.  In  this  way,  a red  amorphous 
powder,  with  a melting  point  range  of  about  200°,  is  obtained. 

As  the  condensation  products  of  both  pyro catechol  and  hydroquinone 
give  white  compounds  with  definite  melting  points,  it  is  to  be 
expected  that  resorcinol  ether  should  be  a product  of  the  same 
type.  Meyer  and  Marx1  have  practically  shown  that  the  red  powder 
is  a mixture  of  substances.  They  isolated  a product  of  the  formula 
C14H12O3  from  the  reaction  mixture  obtained  by  heating  resorcinol; 
or  better,  by  heating  it  with  zinc  chloride. 

It  is  therefore  the  purpose  of  this  thesis  to  attempt  to 
prepare  resorcinol  ether  by  synthetic  methods  with  a view  of 
refuting  the  statement  in  the  literature  that  the  red  amorphous 
substance  is  a simple  substance.  With  this  in  mind,  the  work  on 
the  analysis  of  the  condensation  product  of  resorcinol  may 
proceed. 


5. 


THEORETICAL  AND  HISTORICAL. 

In  the  preparation  of  m-m'-dihydroxy-diphenyl  ether,  it  was 
deemed  advisable  to  make  a diphenvl-ether  derivative  early  in  the 
synthesis,  and  then  to  react  it  in  such  a manner  that  the  groups 
on  the  rings  would  be  changed  or  replaced  in  a definite  manner. 

The  one  that  suggested  itself  first  was  to  prepare  the  ether 
by  reacting  resorcinol  mono-methvl  ether  with  metallic  aluminium. 


£ cu/r  £ 


p 

According  to  the  literature  , the  main  reaction  should  be  the 
formation  of  m-m-dimethoxy-dipheny 1 ether.  By  fractionating  from 
ten  to  twenty  times,  a pure  product  should  be  obtained.  Having  the 
m-m’-dira ethoxy -diphenyl  ether,  it  could  be  treated  with  hydriodic 
acid,  when  it  would  form  m-m-dihvdroxy-diphenyl  ether  and  methyl 
iodide . 

Another  method  would  be  to  go  through  a long  series  of 
reactions  starting  with  p-p’-dinitro-diphenyl  ether.  The  first 
reference^  to  this  particular  compound  in  the  literature  advised 
heating  a mixture  of  p-nitro-chloro -benzene,  p-nitro-phenol , and 
potassium  hydroxide  on  a bath  at  225°.  Later  experiments^  showed 
that  the  reaction  went  less  than  1%;  but  by  using  metallic  copper, 
and  p-nitro-bromo -benzene  in  place  of  p-nitro-chloro-benzene,  a 
yield  of  over  90%  was  obtained.  Another  experiment''  showed  that  even 
if  copper  were  used  to  catalyze  the  reaction,  a yield  of  only  25% 
could  be  obtained  if  p-nitro-chloro-benzene  was  used. 


The  next  step  is  to  reduce  the  p-p’-dinitro -diphenyl  ether 
to  p-p’-di  amino -diphenyl  ether.  It  was  recommended^  to  Use  zinc 
and  hydrochloric  acid.  However,  it  was  thought  that  iron  filings 
and  a trace  of  ferrous  chloride  would  be  active  enough  to  reduce 
this  particular  compound. 

The  amine  groups  of  the  p-p-dinitro-diphenyl  ether  must  be 
protected  with  acetyl  groups  during  the  subsequent  nitration. 
Theoretically,  the  acetylation  is  very  simple.  Dissolving  the 
p-p’-di amino -diphenyl  ether  in  glacial  acetic  acid  and  warming  on 
the  steam-cone  should  be  sufficient  to  acetylate  completely. 

In  the  nitration,  it  was  desired  to  make  a nitro  group  go 
onto  each  ring  in  a position  meta  to  the  ether  grouping.  This 
is  best  accomplished  in  an  acetic  acid  solution,  without  warming. 
However,  concentrated  sulfuric  acid  is  generally  accepted  as  an 
excellent  nitrating  medium,  and  might  prove  more  successful  than 
the  glacial  acetic  acid,  even  though  sulfuric  acid  tends  to  make 
the  nitro  group  go  in  the  ortho  position. 

The  plans  after  having  nitrated  successfully,  were  to  split 
off  the  amino  groups  by  diazotizing,  and  then  replacing  the 
diazo  group  with  hydrogen,  in  an  anhydrous  solution  of  a higher 
al cohol . 

The  m-m’-dinitro -diphenyl  ether  wa3  then  to  be  reduced, 
again  using  iron  filings  and  a few  drops  of  hydrochloric  acid. 

The  diazonium  derivative  would  then  be  prepared  by  means  of 
nitrous  acid  in  a cold  solution.  The  solution  would  be  boiled 

in  a very  large  volume  of  water  to  decompose  the  diazonium  group 
writh  a liberation  of  nitrogen  with  the  formation  of  a hydroxy 
group.  A large  volume  of  water  is  necessary  in  this  reaction 


■ 


' 

■ 


1 

r 


- 


7. 


in  order  tc  prevent  as  much  as  possible  the  formation  of  tars. 

A third  method  of  synthesis  begins  with  m-nitro-bromo -benzene 
and  m-nitro-phenol . These  particular  compounds  were  thought  to  be 
difficult  to  prepare,  but  with  good  m-nitraniline,  the  reaction 
should  go  in  very  good  yields.  In  each  of  the  preparations, 
m-nitro-benzene-diazonium  sulfate  is  prepared  first.  To  make  the 
former,  this  is  warmed  with  cuprous  bromide;  and  for  the  latter, 
it  is  boiled  with  a very  large  volume  of  water. 

As  the  bromine  atom  met a to  a nitro  group  is  supposedly 
very  unreactive,  difficulty  may  be  encountered  in  forming  the 
ether.  However,  if  even  a very  small  yield  would  be  obtained,  it 
would  be  encouraging,  since  when  the  m-m’-dinitro-diphenyl  ether 
is  at  hand,  all  that  need  be  done  to  prepare  the  m-m’-dihydroxy- 
diphenyl  ether  would  be  to  reduce,  diazotize,  and  decompose  the 
diazonium  group  by  boiling. 


8. 


EXPERIMENTAL. 

Preparation  of  ra-m’-dimetho xy -diphenyl  ether. 

Thirty  grams  of  resorcinol  mono-methyl  ether  and  six  grams 
of  aluminium  foil  were  put  in  a small  flask  and  connected  to  a 
reflux  condensor.  A crystal  of  iodine  was  then  dropped  through 
the  condensor  and  a flame  put  under  the  flask.  In  about  fifteen 
minutes  signs  of  reaction  were  noticed,  and  the  burner  was 
removed.  The  reaction  gained  in  velocity  until  it  became  so 
vigorous  that  wet  cloths  had  to  be  applied  to  prevent  the  mixture 
from  coming  out  of  the  top  of  the  condensor.  When  the  reaction 
had  subsided,  the  mixture  was  destructively  distilled  in  order 
to  decompose  the  alminium  triphenolatederivative  of  resorcinol 
mono-methyl  ether.  It  began  to  distill  over  at  about  100°,  and 
when  it  had  reached  £90°  no  more  could  be  made  to  distill.  A 
blue-black  glistening  char  was  all  that  was  left  in  the  distilling 
flask.  It  was  then  attempted  to  distill  and  fractionate  the 
distillate  from  decomposition.  Several  cuts  were  made,  but  most 
of  it  seemed  to  boil  around  243°,  the  boiling  point  of  resorcinol 
mono-methyl  ether.  If  it  had  been  known  where  m-m'-dimethoxy- 
diphenyl  ether  boiled,  very  likely  some  of  it  could  have  been 
isolated  by  cutting  the  fractions  at  the  correct  points;  but  as  it 
was,  nothing  was  known  about  this  particular  compound. 


9. 


Preparation  of  p-nitro-bromo -benzene . 

In  a 500  cc.  flask  was  placed  60  cc.  nitric  acid(sp.gr. 1.42 ) 
and  to  this  was  carefully  added  60  cc.  sulfuric  acid (sp.gr . 1.84 ) . 

When  thoroughly  cooled  to  room  temperature,  40cc.  of  bromo-benzene 
was  added  in  very  small  portions,  shaking  continually.  The  solution 
had  a tendency  to  get  quite  hot,  so  it  was  cooled  by  allowing  tap- 
water  to  flow  over  the  flask.  Large  clods  of  p-nitro-bromo -benzene 
precipitated.  When  the  reaction  had  calmed,  and  showed  no  tendency 
to  heat  up,  it  was  placed  on  a steam-cone  for  an  hour,  and  then 
poured  into  200  cc.  wrater.  The  precipitate  was  filtered  off,  and 
washed  well  with  water  to  remove  the  acids. The  mixed  p-  and  o-nitro- 
bromo-benzene  was  dissolved  in  hot  alcohol,  and  then  cooled.  The 
p-nitro-bromo-benzene  crystallizes  out  when  the  solution  is  cooled, 
while  the  o -nit ro -bromo-benzene,  which  is  fairly  soluble  in  alcohol, 
remains  in  solution.  The  yield  was  50  grams,  or  76%, 

Preparation  of  potassium  p-nitro -phenol ate. 

Twenty  grams  of  K0H  was  dissolved  in  100  cc.  water,  and  added, 
with  stirring,  to  70  grams  of  p-nitro -phenol  in  200  cc.  water. 

The  suspension  was  boiled  until  it  dissolved.  It  was  then  cooled. 

The  thick  precipitate  which  formed  was  sucked  free  from  the  liquid 
by  using  a Buchner  funnel.  The  crystals  were  then  washed  with  several 
small  portions  of  alcohol.  It  is  of  a deep  yellow  color. 


10. 


Preparation  of  p-p-dlnltro -diphenyl  ether. 


One  hundred  and  fifty  grams  of  p-nitro-bromo -benzene  was 
thoroughly  mixed  with  112  grams  of  potassium  p-nitro -phenol ate 
in  a large  flask,  and  about  one-half  gram  of  pulverized  copper 
added  to  catalyse  the  reaction.  The  mixture  was  heated  on  the 
steam-bath  for  several  hours,  and  then  on  an  oil  bath  for  several 
days  at  a temperature  of  about  175°  and  not  exceeding  190°.  At  the 
end  of  this  time  the  mixture  was  leached  with  water  to  wash  out 
the  KBr  and  unreacted  potassium  p-nitro -phenol ate.  The  excess  of 
p-nitro-bromo-benzene  was  removed  by  prolonged  steam  distillation. 
The  condenser  was  omitted  and  the  steam  run  under  water,  as  the 
product  solidified,  clogging  up  the  tube.  The  brown  mass  remaining 
in  the  flask  was  extracted  with  benzene.  The  first  extractions 
needed  no  recrystallization,  but  the  later  ones  had  to  be  re- 
crystallized from  hot  alcohol.  Some  of  the  lower  melting  portions 
(85°-93°)  could  not  be  purified.  The  yield  of  product  melting  at 
138°  was  35#.  On  some  of  the  rune  no  p-p-dinitro -diphenyl  ether 
could  be  isolated,  due  perhaps  to  the  excessive  heating  above  200°. 

A mixture  melting  between  84°  and  95°  was  the  only  product  obtained. 

P-nitro-chloro-benzene  was  used  in  several  of  the  runs  in 
place  of  the  p-nitro-bromo-benzene,  but  practically  all  of  the 
original  substances  was  recovered ■ uncombined. 


Care  must  be  t en  to  heat  the  mixture  rather  slowly. 


because  if  heated  too  rapidly,  the  reaction  is  very  liable  to 
become  quite  violent. 


11. 


Preparation  of  p-p-di amino -diphenyl  ether. 

Fifty  grams  of  p-pt-dinitro -diphenyl  ether  was  mixed  with  a 
large  excess  (about  150  grams)  of  iron  filings.  Enough  water  was 
added  to  form  a thick  paste,  and  this  was  followed  by  a few  drops 
of  concentrated  HC1.  During  most  of  the  time  of  the  reaction,  which 
was  strongly  exothermic,  the  mixture  was  vigorously  stirred.  In  a 
couple  of  hours,  when  the  filings  had  cooled  to  some  extent,  it  was 
heated  on  the  steam-cone  to  complete  the  reduction.  The  rapid  evap- 
oration necessitated  an  occasional  addition  of  water.  The  mixture, 
when  it  was  dried  on  the  steam-bath  to  facilitate  subsequent 
extractions,  had  a tendency  to  solidify  in  a hard  cake.  This  was 
overcome  to  a large  extent  by  stirring  frequently.  When  completely 
dry  and  powdery,  the  mixture  was  extracted  with  benzene  to  remove 
the  unreduced  p-p’-dinitro-diphenyl  ether.  The  residue  was  extracted 
with  hot  acetone  until  the  extraction  liquors  from  the  iron  filings 
were  almost  colorless.  The  p-p*-di  amino -diphenyl  ether  was  obtained 
by  just  evaporating  off  the  acetone.  By  this  method  a very  pure 
product  was  obtained,  the  melting  point  range  being  only  two 
degrees.  The  yield  on  the  several  runs  averaged  80^  of  the 
theoretical . 


Acetylation  of  p -p -di amino -qipheny 1 ether. 

Ten  grams  of  p-pf-di amino -diphenyl  ether  was  dissolved  in  100 
grams  of  acetic  anhydride  (tech),  and  heated  on  a steam-bath  for 
three  days.  At  the  end  of  this  time,  the  solution  was  poured  into 
?00  cc.  water.  It  did  not  mix,  but  formed  an  oil  which  was  decom- 
posed on  boiling.  As  the  oil  disappeared,  a dark  pink  precipitate 

formed.  After  boiling  for  several  hours,  it  was  filtered. 


. 

Ill 


. 


- . 


- 


. 


- - 

« 


- 

. 


12. 

The  melting  point  remained  constant  after  crystallizing  several 

times  from  ethyl  alcohol, 
acet 

P-p’-d^amino -diphenyl  ether  is  a light  pink  compound  melting 
at  126'-]  27°  ( corr ) . Ethyl  alcohol  and  acetone  dissolve  it  very 
readily,  while  it  is  almost  insoluble  in  benzene  and  ether.  The 
yield  was  85$  of  the  theoretical. 

Analysis:  0.2000  gram  sample;  5.9  cc.  of  0.250  N.HC1;  $ N 
calculated  from  the  molecular  formula-9 .8$;  $ N found-10.1$. 

0.2000  gram  sample;  18.0  cc.  N at  28°C  and  746.7  mm. 
$ N calculated  from  the  molecular  formula-9 .8$;  $N  found-9.7$. 

As  the  calculated  f of  N for  the  mono-acetyl  derivative  is 
11.5$,  these  analyses  show  conclusively  that  the  compound  obtained 
was  p-p-di acet amino -diphenyl  ether. 

Nitration  of  p-p-di acet amino -diphenyl  ether. 

It  was  first  attempted  to  nitrate  the  p-p’-diacet amino -diphenyl 
ether  with  the  theoretical  quantity  of  fuming  nitric  acid.  Six 
grams  of  the  ether  was  dissolved  in  15  cc.  glacial  acetic  acid. 

To  this  was  slowly  added  a mixture  of  2 cc.  fuming  nitric  acid, 

5 cc.  glacial  acetic  acid,  and  .1  gram  urea,  the  latter  being  for 
the  purpose  of  preventing  oxidation.  When  one  and  one-half  cc.  of 
the  nitric  acid  solution  had  been  added,  the  solution  of  the  ehher 
changed  from  a deep  red  to  a light  yellow.  The  change  in  color 
had  taken  place  slowly.  Then  suddenly,  when  about  2 cc.  was  added, 
the  solution  turned  dark  red  again,  and  remained  so  during  the 
addition  of  the  rest  of  the  nitric  acid.  The  flask  was  allowed  to 
stand  in  a cool  place  over  night.  In  the  morning,  while  shaking 
and  examining  the  contents  of  the  flask,  the  mixture  suddenly 


13 


solidified  to  a mass  of  bright  yellow  crystals;  not  a trace  of  the 
red  coloration  remained.  After  letting  stand  a day  longer  to  be 
assured  of  complete  nitration,  water  was  added,  and  the  acetic  acid 
sucked  from  the  crystals.  They  were  then  washed  free  from  acid 
with  water. 

The  nitration  product  was  partly  soluble  in  alcohol.  The 
filtrate  from  the  first  washings  was  reddish-brown;  but  after  washing 
several  times,  the  alcohol  came  through  almost  colorless.  The 
compound  was  dried,  and  found  to  melt  197  and  199°:  it  had  previously 
at  various  stages  in  the  purification  melted  at  points  ranging  from 
160°  to  206°.  Six  grams  of  product  was  obtained. 

Analyses:  0.3000  gram  sample;  369.0  cc.  C0g  collected  at  23° 
and  740.0  mm;  $ C calculated  for  C^qHj(.0^N,7-58 . 3$;  $ C found-58.0^. 

0.2000  gram  sample;  23.7  cc.  N collected  at  742.6  mm. 
and  28°;  $ N calculated  for  C^H^OgN^-12.8^;  «f;  ^ found-12.7$. 

As  the  mono-nit ro  derivative  of  p-p-diacet amino -diphenyl  ether 
was  conclusively  obtained,  an  effort  was  made  to  put  another  nitro- 
group  on  by  using  a 100^  excess  of  fuming  nitric  acid,  but  the 
mono-derivative  was  obtained  in  this  case  also. 

Then  heating  was  tried.  Two  grams  of  p-p-diacet  amino -mono - 
nitro-diphenyl  ether  was  dissolved  in  glacial  acetic  acid,  and  the 
theoretical  amount  of  fuming  nitric  acid  added.  It  was  heated  on 
the  steam  cone  for  one  day,  and  then  cooled.  As  no  precipitate 
formed,  it  was  poured  into  water.  Everything  was  completely 
soluble  to  a yellowish  solution,  except  for  a small  amount  of 
very  fine  black  powder.  Not  enough  of  it  was  collected  to  analyze, 
but  it  was  assumed  to  be  carbon.  On  making  the  solution  alkaline, 
it  became  red,  but  no  precipitate  formed.  Apparently,  the  ether 


14 


broke  down  into  a phenol. 

Concentrated  sulfuric  acid  was  then  tried  in  place  of  the 
acetic  acid.  In  the  cold,  p-p’-diacetamino-mono-nitro-diphenyl  ether 
was  isolated;  and  on  warming,  it,  too,  decomposed,  giving  compounds 
soluble  in  both  dilute  acids  and  alkalies. 

As  no  p-p’-di  acet  amino -ra-m-dinitro -diphenyl  ether  was  obtained 
by  any  of  these  methods,  work  on  this  series  of  preparations 
was  suspended. 


- 


15. 


Preparation  of  m-nitro -benzene-diazonium  sulfate. 

Fifty  grams  of  m-nitraniline  was  suspended  in  200  cc.  water, 
and  100  co.  cone,  sulfuric  acid  added  with  stirring.  In  some  cases 
it  may  be  necessary  to  warm  on  the  steam-cone  to  completely 
dissolve  it.  The  hot  solution  is  poured  with  stirring  into  a large 
beaker  containing  a liter  of  water  and  cracked  ice.  A fine  pink 
precipitate  separates.  When  the  temperature  reached  0C,  26  grams 
of  sodium  nitrite  disolved  in  150  cc.  water  was  added  rapidly 
with  stirring.  The  temperature  should  be  kept  as  low  as  possible, 
preferably  below  5°.  In  a few  minutes,  the  solution  was  filtered. 


Preparation  of  m-nitro -phenol . 

For  each  25  grams  of  m-nitraniline  used  in  preparing  the 
m-nitro -diazonium  sulfate,  300  cc.  cone,  sulfuric  acid  diluted 
to  two  liters  was  added.  The  total  volume  was  about  eight  liters. 
The  solution  was  heated  in  a large  copper  can.  At  about  85°,  the 
nitrogen  began  to  come  off  with  vigorous  bubbling.  When  it  began 
to  boil, it  became  quite  turbid,  but  after  boiling  for  thirty 
minutes,  it  became  clear,  with  some  tar  floating  on  the  surface. 
It  was  filtered  hot  through  a Buchner  funnel  prepared  by  placing 
one  inch  sand  on  top  of  the  funnel  to  prevent  the  tar  from  going 
through.  Before  using,  the  sand  should  be  treated  with  1:1 
sulfuric  acid. 

When  cold,  the  filtered  solution  was  thoroughly  extracted 
with  ether.  When  the  acid  solution  no  longer  becomes  red  when 
made  alkaline,  the  m-nitro -phenol  lias  been  removed. 


16 . 

After  distilling  off  the  ether  as  completely  as  possible,  the 
remaining  oil  should  crystallize.  In  most  of  the  cases  no  difficulty 
was  encountered;  however,  if  even  a small  amount  of  water  is  present, 
the  crystallization  will  be  hindered,  or  even  prevented.  The  crystals 
were  washed  with  benzene  until  they  were  of  a light  cream  color.  The 
benzene  used  in  washing  was  added  to  the  mother  liquors  and  distilled 
off. 

It  was  found  that  a much  better  product  could  be  obtained  by 
dissolving  the  m-n it ro -phenol  in  hot  1:1  HC1.  After  cooling  to  about 
40°  the  solution  was  decanted,  or  filtered  if  necessary,  and  allowed 
to  cool  slowly,  finally  placing  the  beaker  in  ice  water.  Beautiful 
large  white  crystals  of  very  pure  m-nitro -phenol  formed.  A yield 
of  70^  was  obtained. 

Preparation  of  potassium  m-nit ro -phenol at e . 

Twrenty  grains  of  KOK  was  dissolved  in  100  cc.  water,  and  added 
slowly  with  stirring  to  a suspension  of  70  grams  of  m-nitro -phenol 
in  200  cc.  water.  After  boiling  for  a short  time,  the  phenol 
dissolved.  The  mixture  was  allowed  to  cool.  When  it  became  a solid 
thick  mass,  the  liquid  was  sucked  off  in  a Euchner  funnel.  After 
washing  several  times  with  small  portions  of  alcohol,  the  crystals 
lost  their  deep  red  color,  and  became  a reddish  orange. 

A considerable  amount  of  potassium  m-nitro -phenol ate  may  be 
recovered  from  the  liquors  sucked  through  the  funnel  by  evaporating 

to  a rather  small  volume,  and  allowing  to  cool  in  the  same  manner 
as  the  original  solution. 


- 


- 


- 


17 


Preparation  of  m-nitro-bromo -benzene. 

In  a two  liter  flask  was  put  45  grains  of  crystallized  copper 
sulfate,  150  grams  of  KBr,  150  cc.  water,  P0  grans  of  copper  turnings 

7 

and  9 cc.  of  concentrated  sulfuric  acid  . The  flask  was  connected 
to  a reflux  condensor,  and  heated  on  a flame  until  the  solution  \vas 
colorless.  If  sulfur  dioxide  is  passed  in,  the  reduction  takes  place 
much  more  rapidly.  However,  the  excess  must  be  boiled  out. 

In  the  meantime  a solution  of  m-nitro-benzene-diazonium  sulfate 
was  prepared,  using  50  grans  of  m-nit rani line . Both  of  the  solutions 
should  be  ready  for  use  at  the  same  time 

The  m-nitro-benzene-diazonium  sulfate  was  added  slowly  to  the 
cuprous  bromide  solution,  which  was  removed  from  the  free  flame 
and  placed  on  the  steam  bath  to  facilitate  the  vigorous  shaking 
which  is  necessary.  The  solutions  should  be  kept  as  hot  as  possible 
and  be  mixed  rapidly  to  insure  a good  yield.  When  all  had  been  added, 
the  m-nitro-bromo-benzene  was  distilled  over  with  st9am.  It  was 
filtered  from  the  water  and  dried.  The  product  was  quite  pure,  and 
needed  no  further  furif ication.  The  yield  was  75fo. 

Preparation  of  m-m-dinitro -diphenyl  ether. 

Fifty-six  grams  of  pot as sium-m-nitro -phenol ate  was  thoroughly 
mixed  with  a slight  excess,  75  grams,  of  m-nitro-bromo-benzene,  and 
about  one-half  gram  of  powdered  copper.  The  flask  was  connected  to 
a reflux  condensor,  and  left  on  the  steam  bath  for  several  days. 

The  mixture  became  semi-solid.  Then  it  was  put  in  an  oil  bath,  and 
heated  up  very  slowly  until  it  reached  150°,  where  it  was  held  for 
about  five  hours.  After  this  time,  indication  of  charring  were 


18 


noticed  by  the  black  deposits  around  the  edges.  The  mixture  was 
cooled,  water  added,  mixed  well,  and  decanted.  The  potassium-m-nitro- 
phenolate  which  crystallized  out  from  the  wash  water  was  recovered. 
After  removing  the  excess  of  m-nitro-bromo -benzene  by  steam- 
distillation,  the  residue,  which  was  in  the  form  of  dark  brown 
pellets,  was  ground  in  a mortar,  leached  with  water,  and  again  steam- 
distilled,  for  the  purpose  of  removing  the  last  traces  of  potassium- 
m-nitro -phenol ate  and  KBr,  and  m-nitro-bromo -benzene  respectively. 
After  this  treatment,  the  product  was  dissolved  in  benzene.  On 
evaporating  the  solution  a product  solidified  out  which  had  a 
melting  point  range  from  105°-120c.  Recrystallization  from  hot  alcoho] 
was  tried,  but  the  melting  point  did  not  change  more  than  a few 
degrees,  the  main  range  being  quite  constant.  Acetone  and  ether 
were  tried  in  both  the  extraction  and  recrystallization,  but  with  the 
same  result. 


19 


SUMMARY . 

None  of  the  methods  tried  for  preparing  m-m’-dihydroxy-diphenyl  - 
ether  succeeded.  The  one  in  which  resorcinol  mono-methyl  ether  was 
used  may  have  remote  possibilities.  The  second  synthesis,  that  in 
which  the  reaction  are  carried  on  from  p-p'-dinitro-diphenyl  ether, 
was  entirely  unsuccessful,  due  to  the  inability  to  prepare 
m-rc-dinitro-p-p-diacet  amino -diphenyl  ether,  getting  instead  only 
mono-nitro-p-p-diacetamino-diphenyl  ether.  The  method  starting 
with  m-m-dinitro -diphenyl  ether  seems  to  be  promising,  if  work  on 
this  problem  were  to  be  continued,  the  author  would  suggest  that 
synthesis  which  starts  with  m-nitro-bromo-benzene  and  potassium- 
m-nitro -phenol ate,  because  of  the  few  steps  in  the  synthesis,  and 
the  smoothness  with  which  they  should  go,  with  the  exception  of 
the  coupling  of  the  first  compounds  to  form  the  ether. 


_ 


20 


BIBLIOGRAPHY. 


1. 

Ber . 

40 

1450-53 

(1907  ) 

2. 

Ber . 

12 

1925  (1879  );  14 

3. 

Ber. 

29_ 

1448 

4. 

Ber. 

38 

2211 

5. 

Ann. 

550 

83-107 

(1906  ) 

6 . 

Ber. 

29 

1449 

7.  Noyes  Org.Chem.  P.202 


(1881  ) 


